1. Field of the Invention
This invention relates in general to bag assemblies for upright vacuum cleaners, and more particularly, to a re-useable cloth bag treated with a dual component antimicrobial treatment which prevents the build-up of bacteria and fungi within the bag and the bag's fibers.
2. Description of the Prior Art
A vacuum cleaner removes dirt, dust and other foreign material from a surface being cleaned and deposits them in a dirt collecting bag. The vacuum cleaner main housing carries a vacuum generating means referred to as a "motor-fan unit" which creates a flow of dirt laden air through the housing into the dirt collecting bag. The vacuum pressure generated in the main housing draws the dirt laden air through the housing and through an air duct into the dirt collecting bag which is attached by a mouth opening to the air duct.
The dirt collecting bag is formed with a porous material, such as cloth, and functions to filter all the dirt laden air and collect the dirt and dust within the bag. Filtered air passes through the bag's sidewalls and is exhausted into the atmosphere. Commercial upright vacuums often feature a dirt collecting bag of simple cloth construction. Unlike many home vacuum cleaners with disposable paper filters, the cloth commercial bag is re-used repeatedly during the twelve to sixteen month lifespan of the bag. After the bag fills with dirt, the user removes the bag from the vacuum cleaner housing and dumps the dirt through an end opening into the trash. The bag is then reinstalled and the process is repeated.
The reusable nature of the bags creates potential problems in commercial and industrial applications, such as hospitals, doctor's offices, hotels, restaurants, dealers in rental goods, and the like. During business hours, a large number of people pass through the work areas. These people include both the employees and the patrons of the establishments. For example, in a pediatrician's office, many children with their parents enter the office in any one day. Most children are healthy and present for a check-up. Other children have a wide range of problems from diseases to wounds and injuries. Whether healthy or ill, the patients can cough, sneeze and track microorganisms into the office and on the carpeting.
Another example is a restaurant. During the course of the day, food and dirt particles constantly drop to the floor. Patrons bring into the restaurant all the microbiological flora on their clothes and person. Diners remove their jackets, brush their clothes, rub their hands. They wipe food from their mouths which falls to their laps. The diners leave the table and brush the food particles from their laps, effectively brushing other particles from their clothing. Patrons may use the toilet, tracking microorganisms from the toilet area back into the dining area. Both spills and cleaning tables moisten the floor.
The mere presence of people enriches the environment for microbes. Humans naturally shed skin cells and hair during the course of a day and with them their microbiological flora. Proper hygiene, such as hand washing, reduces the amount of microbiological flora. Unfortunately, proper hygiene is difficult to enforce within the public domain.
All of these particles of food, dust, dirt, skin cells, hair, and the like provide an excellent medium for bacterial and fungal population growth. A good vacuum cleaner picks up these particles from the floor and deposits them into the bag. This also inoculates the bag with the bacteria and fungi associated with the particles. A vacuum cleaner bag thus provides a rich environment for growth if sufficient water is present. The bag is enclosed and at warm temperatures, ideal conditions for the proliferation of many microorganisms. Every time the bag is used, more "growth medium" and more inoculum are deposited and concentrated within the bag. Dumping the bag decreases the amount of material for microbiological growth. However, the microorganisms can still grow on the remaining residue within the bag and on the bag fibers. In many commercial situations, frequent dumping of the bag's contents is rare. Even if the microbes do not grow, they can still survive inside the bag in a stationary cycle of cell growth.
For example, testing the fabric and contents from a used vacuum cleaner bag yielded large numbers of bacteria and fungi. A bag from a restaurant had almost one hundred times more bacteria per square inch of fabric than two other bags used while cleaning other commercial establishments. The restaurant bag yielded approximately one million bacteria/sq. in. when grown under conditions which select for bacteria. Many of the bacteria were benign and of the strains normally associated with the soil. This same bag also contained Staphylococcus strains normally associated with the human skin and enteric bacteria associated with human feces. Fungi were recovered from all three bags at approximately ten thousand fungi/sq. in. when grown under conditions selective for fungi. The predominant types appeared to be of the PenciIIium genus and black spore formers.
While most microorganisms found within a vacuum cleaner bag are harmless, others are not. Some microorganisms have the capability of becoming opportunistic pathogens. Strains of bacteria, such as members of the Bacillus genus, are common food spoilage organisms and can cause severe food poisoning, for instance, B. cereus. Other Bacilli, B. anthracis for example, are highly infectious pathogens. Members of the Staphylococcus bacterial genus vary from the benign to the pathogenic, for example food poisoning and other illnesses such as hospital-acquired infections. Staphylococcus requires little water for survival and can easily proliferate within the confines of a vacuum cleaner bag and its fibers when conditions are favorable, such as the increase in moisture content after vacuuming up damp debris. Fungi, such as Asperigillus niger, often grow on fabric of the bag, causing undesirable discoloration. This fungal growth may reduce the fabric's tensile strength which weakens the fabric and leads to tearing and a premature reduction in the bag's lifespan. Some fungi are associated with food spoilage and some are human pathogens, for example, the yeast Candida albicans. Many bacteria and fungi contribute unpleasant odors and undesirable stains to the bag. Further, microbial growth on the fabric poses a health hazard if pathogenic strains establish a niche and proliferate.
The process of cleaning stirs up aerosols of dust, dirt particles, bacteria and fungi from the carpeting. These aerosols are a good method of transferring microorganisms from room to room. A good vacuum cleaner bag effectively filters the particles, but cannot sterilize the air vented through the pores of the fabric. A pore size adequately small to filter out bacteria clogs easily. A vacuum cleaner bag with clogged pores, cannot adequately discharge the air to the atmosphere and suction up the dirt. Clogged pores prematurely reduce the life of a bag.
Even if the vacuum cleaner bag does not directly contaminate the various areas of use, the bag can contaminate the vacuum cleaner users. Cleaning personnel do not usually use gloves and masks when dumping the contents of a vacuum cleaner bag. During dumping, aerosols of debris form around the trash receptacle and contaminate the atmosphere. Cleaning personnel breathe this debris as well as contaminate their clothing and exposed skin and hair. These workers leave this trash area and seed the areas they enter.
In the past some techniques were developed to reduce the problems associated with the build-up of dirt within the vacuum cleaner bag. For example, U.S. Pat. No. 4,675,032, issued Jun. 23, 1987, and assigned to the assignee of the present invention, provided a substantial improvement in nondisposable cloth bags. The invention incorporated an "oscillator tube" within the bag interior which served to vibrate the bag in use and prevent buildup of dirt on the bag's interior sidewalls. Because dirt buildup was reduced, the bag was cleaner in operation.
Other prior art techniques are ineffectual for preventing microbiological growth in a reusable cloth vacuum cleaner bag. Some filter the dust and dirt. Filtering the exhausted air through a vacuum cleaner bag does not prevent microbiological growth within the bag. Filtering merely prevents the larger dirt particles from exhausting with the air.
Some prior art techniques from the past fifty years suggest using some type of chemical treatment such as disinfectants or deodorants. However, this prior art either uses general terms such as "sticky germicidal substance", U.S. Pat. No. 2,188,428, or vaguely mentions some chemical treatment to inhibit microbiological growth, U.S. Pat. No. 3,907,530, or to treat the exhausted air, U.S. Pat. No. 2,272,394. While this prior art agrees that microbial contamination of the vacuum cleaner bag is a problem, it does not reveal a specific remedy.
Actual antimicrobial treatments have been described for some time, although to the best of Applicant's knowledge these treatments are not applied to nondisposable cloth vacuum cleaner bags and never in combination with Applicant's "oscillator." This is due, in part, to the fact that the available antimicrobial treatments were not practical for use in an application such as a cloth vacuum cleaner bag. For example, members of the class of antifungal agents, the bromosalicyl anilides, are highly insoluble in aqueous solutions, requiring solubility in N,N-Dimethylformamide which is highly flammable and can dissolve many synthetic fibers. Another class of antimicrobials are members of the phenol family, such as o-phenyl phenol which is a carcinogen as well as a fungicide and a bactericide. Phenols are poisonous and chronic poisoning is known in industrial settings. The antimicrobial agent hexachlorophene is a potential neurotoxin that is regulated by the FDA. Organoarsenical compounds are hazardous to the environment. The organosilanes covalently bond to the substrate. Although organosilanes are effective against single layers of microorganisms, they are ineffective against clumps of microorganisms. Since organisilanes have not been tested in nondisposable vacuum cleaner bags, their effectiveness in the bag environment is unknown. Neomycin sulfate and other similar antibacterial agents require uptake into the cell. Uptake requires the agent to detach or leach from the substrate in order to enter the cell. This leaching reduces the amount of agent available to attack the microbes during the lifetime of the vacuum cleaner bag.
Other techniques describe treating disposable, paper vacuum cleaner bags. For instance, one technique describes treating a disposable paper vacuum cleaner bag with humic acid, a treatment ineffective in reducing microbial growth in practice. Japanese Patent Application No. SHO61-271013. Other techniques require the use of disposable bags, paired with additional inserts which are costly and not used in commercial applications. See, for example, U.S. Pat. No. 3,274,758 (envelope with volatile deodorant granules), and U.S. Pat. No. 5,040,264 (strip impregnated with chemicals). These techniques require the replacement of the insert with a fresh insert with new chemicals each time the bag is dumped. Apparently the treatment loses effectiveness through the volatility or instability of the chemicals used. The inserts do not work on nondisposable bags because there is no way to replace them each time the bag is dumped. The inserts cannot be simply thrown loosely into the bag, but must be attached within the bag. If these inserts are not attached, they can fall into the mouth opening of the bag, therefore reducing the efficiency of the vacuum cleaner. Another technique suggests vacuuming a substance into the bag, which needs an antimicrobial treatment with a solid volatile component.
Some disinfectants are volatile. The amount of active disinfectant incorporated onto the vacuum cleaner bag fabric can be substantially reduced at the high temperatures used in textile manufacturing. The vacuum cleaner bag also heats during use, increasing the volatility of the disinfectant. The amount of disinfectant is further reduced with every use. The volatile disinfectant exhausts through the pores of the bag into the outside air, consequently exposing the vacuum cleaner user to the emissions.
To the Applicant's best knowledge, none of the prior art describes the efficacy of such antimicrobial treatment. One item of prior art calls for a fresh bag and treatment every time the bag is dumped, thereby suggesting the treatment has a only a short period of effectiveness. U.S. Pat. No. 5,040,264. None of the prior art describes whether the treatment is effective against bacteria and/or fungi. Many disinfectants are effective against only one type of microbe and not the other. For example, disinfectants often have more than one active ingredient, which improves the disinfectant spectrum of activity. Furthermore, disinfectants with more than one active ingredient inhibit microorganisms from acquiring resistance to the disinfectant.
Efficacy of the disinfectants is rated by testing the effectiveness of the concentration of their active ingredient(s) against various microorganisms over a certain length of time. Some of these variables affect how broad the spectrum of activity is and the length of time the activity lasts. Therefore, efficacy depends on concentration and time after manufacture.
Effective disinfectants are potent chemicals. Disinfectants often create problems to the people exposed to them and to the environment. Some people exposed to the disinfectants become sensitized to them. Sensitization causes physical problems ranging from contact dermatitis to severe allergic reactions such as asthma. Incorrectly used, disinfectants can harm the people who come in contact with them. Disinfectants can also contaminate the ground or water when incorrectly used and disposed.
Because of the problems associated with chemical treatments of vacuum cleaner bags, safety, efficacy and toxicity of antimicrobial treatments are of vital concern. One object of the present invention is to produce an effective composition with antibacterial and antifungal activity to treat a nondisposable, cloth vacuum cleaner bag that is safe to use.
The present invention also has as its object the provision of a bag for a vacuum cleaner which greatly reduces the chances of harboring harmful bacteria and fungi for the life of the bag, even when the bag is repeatedly re-used in commercial applications.
Another object of the invention is the provision of a vacuum cleaner bag which is treated with an antibacterial and antifungal composition. The antimicrobial composition attaches to the material of the bag and inhibits the growth of bacteria and fungi and remains effective for the life of the bag.
Another object of the present invention further reduces the growth of potentially dangerous bacteria and fungi within cloth vacuum cleaner bags by utilizing a method of treating the bags with an antibacterial and antifungal composition. This treatment attaches the antimicrobial composition to the bag's fabric.
Additional objects, features and advantages will be apparent in the written description which follows.